[amsat-bb] Re: The Moon is our Future / antennas
la2qaa at hotmail.com
Sat Jul 4 05:00:21 PDT 2009
Principally, the same as the Fyllingsdales BMEWS steerable phased array, yes ??.
We have some info on it on OBSERVATIONS.
73 John. <la2qaa at amsat.org>
> From: G0MRF at aol.com
> Date: Fri, 3 Jul 2009 19:21:08 -0400
> To: kd6ozh at comcast.net; amsat-bb at amsat.org
> Subject: [amsat-bb] The Moon is our Future / antennas
> In a message dated 03/07/2009 20:46:44 GMT Standard Time,
> kd6ozh at comcast.net writes:
> Building a prototype that works on Earth for project like this is only a
> few percent of the effort required. Treating it as a radio club project
> won't be effective as people need to sign up for a 5-year project.
> Hi all.
> John is absolutely right in saying the complexity cannot be easily compared
> to a terrestrial radio project. One other thing that stands an almost zero
> chance of succeeding is a dish antenna that needs to point towards the
> earth. If NASA and the ISS have trouble with moving parts on the solar array
> you can imagine how much more difficult it would be on the moon.
> However, how about this.
> The problem with the higher bands is power generation / path loss / antenna
> gain. Any higher band like 1.2, 2.4 or 5.8G would need a high gain antenna
> to offset the increased path loss.
> But, instead of a conventional steerable dish....with its unreliable moving
> joints...How about an electrically steerable array of patches / dipoles /
> or any other type of antenna element.
> But how to 'point' it?
> Well. actually I think Tom Clark provided the answer for that with his
> proposal of a few years ago. The principle is this: If you have 2 arrays. One
> say on 5.6G uplink and one on 5.8G downlink, then the receiving array can
> electrically look in different directions for a signal from the Earth.
> Once the receiver has identified a signal and optimised the RX Antenna, the
> information on the direction of the Earth i.e. the direction of the strongest
> incoming signal can be used to configure the transmit array which will
> then beam a signal back to earth with high ERP.
> Directional, high gain, and no moving parts.
> David G0MRF
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